It may be seen, then, that if one was prepared to accept the existence of insulating sheaths on the nerves, all the arguments raised against the proposed identification of the nervous and electrical fluids, except one, could be answered satisfactorily. The single exception involved the question of how an electrical disturbance in the brain could be confined to a single nerve, and, as was indicated earlier, it was scarcely fair to hold this sort of objection against the electrical theory alone. (...) In that case, there remained no convincing argument to show why one should not accept the identification of the two fluids. On the other hand, of course, it remained an open question as to whether there was any convincing argument to show why one should accept the identification either. Galvani thought that his experiments provided just such an argument. (shrink)

In 1880, Charles Darwin publishedThe Power of Movement in Plants, a heavy volume of nearly six hundred pages in which he presented the results of many years of experiments conducted with his son Francis on the reaction of plants to the influence of light and gravity. His results contradicted the observations and explanations of the same phenomena offered by the German plant physiologist Julius Sachs in his influentialLehrbuch der Botanik(1868, English translation 1875). Darwin wished rather to ‘convert him than any (...) other half-dozen botanies put together’. Sachs, however, regarded Darwin's work with contempt. Taking up the topic in hisVorlesungen über Pflanzenphysiologiein 1882 and taking issue especially with Darwin's experiments on the movement of root radicles in reaction to gravity, he remarked sharply: In such experiments with roots not only is great precaution necessary, but also the experience of years and extensive knowledge of vegetable physiology, to avoid falling into errors, as did Charles Darwin and his son Francis, who, on the basis of experiments which were unskilfully made and improperly explained, came to the conclusion, as wonderful as it was sensational, that the growing point of the root, like the brain of an animal, dominates the various movements in the root. (shrink)

In 1675, Burchard de Volder became the first university physics professor to introduce the demonstration of experiments into his lectures and to create a special university classroom, The Leiden Physics Theatre, for this specific purpose. This is surprising for two reasons: first, early pre-Newtonian experiment is commonly associated with Italy and England, and second, de Volder is committed to Cartesian philosophy, including the view that knowledge gathered through the senses is subject to doubt, while that deducted from first principles is (...) certain. On the surface, it is curious that such a man would bring experiments to university physics. After all, in demonstrating experiments to his students, he was teaching them through their senses, not reason. However, if we consider the institutional context of de Volder’s teaching, we come to see de Volder’s Cartesian experimentalism as representative of a certain form of pre-Newtonian Dutch Cartesian science, as well as part of a larger tradition of teaching through observation at the University of Leiden. Considering de Volder’s institutional context will help us see that de Volder’s experimentalism was not in spite of his Cartesianism, but motivated by it. This paper will describe de Volder’s physics curriculum, the Theatre in which it was taught and how his work predates similar efforts in other European Universities. The second part will consider three aspects of the culture at the University of Leiden: a tradition of teaching through observation, a particular reception of Cartesianism, and an eclectic approach to the New Philosophy. The concluding portion shows how de Volder would have understood his enterprise in Cartesian terms. (shrink)